STOCKHOLDERS' EQUITY AND STOCK-BASED COMPENSATION (Common Stock) (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		1 Months Ended		3 Months Ended		4 Months Ended			9 Months Ended	12 Months Ended
	Jan. 05, 2016	Aug. 04, 2015	Feb. 29, 2012	Jun. 30, 2016	Mar. 31, 2015	Nov. 23, 2016	Aug. 04, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Authorized shares of capital stock										3,050.0
Authorized shares of common stock										3,000.0
Authorized shares of preferred stock										50.0
Issuance of common stock								$ 1,000.0			$ 2,366.0	$ 1,936.0
Proceeds from sale of common stock										$ 0.0	1,515.0	$ 1,936.0
Debt Instrument, Face Amount											$ 2,342.0
Common Stock, Dividends, Per Share, Cash Paid		$ 0.1105
Dividends declared per share of common stock (in dollars per share)			$ 1.25		$ 0.20					$ 0	$ 0	$ 0.2605
Common stocks
Class of Stock [Line Items]
Issuance of common stock						$ 1,500.0			$ 1,000.0		$ 20.0	$ 20.0
Stock Issued During Period, Shares, New Issues	4.3			48.1		116.5	27.7				197.0	205.7
Shares Issued, Price Per Share						$ 12.87		$ 9.53				$ 9.53
Proceeds from sale of common stock	$ 29.0					$ 1,500.0	$ 311.0					$ 1,960.0
Proceeds From Issuance Of Common Stock Net						1,480.0						1,940.0
Payments of Stock Issuance Costs	$ 0.3					$ 15.0						$ 20.0
Debt Instrument, Face Amount							$ 369.0
Ultra-deepwater Drillship Contracts [Member]
Class of Stock [Line Items]
Stock Issued During Period, Shares, New Issues				48.1
Proceeds from sale of common stock				$ 540.0
Payments of Stock Issuance Costs				$ 5.0